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Topic: Validation of GCM Models (Read 22937 times)

At the moment, I'm not so interested in notions of verification, "the old guard" & etc but whether the quote posted by AbruptSLR has any credence...

Quote

"Scientists are now saying it might already be too late to avoid a temperature rise of up to 7.36 degrees Celsius (13.25 degrees Fahrenheit) above pre-industrial levels by 2100.That's way above the upper limit of 4.8 degrees Celsius (8.6 degrees Fahrenheit) predicted by the Intergovernmental Panel on Climate Change (IPCC) in 2014, and to make matters worse, a new study suggests that we're underestimating just how sensitive Earth is to greenhouse gases.

Geoff,

So that you can decide for your, I selected the following 28 references [not including either von der Heydt et. al. 2016 nor Friedrich et al (2016)] that either directly, or indirectly, indicate that climate sensitivity is most likely significantly higher than the range summarized by AR5:

3. The linked reference presents new paleo evidence about the Eocene. While the authors emphasize that their findings support the IPCC interpretation for climate sensitivity, when looking at the attached Fig 4 panel f, it appears to me that this is only the case if one averages ECS over the entire Eocene; while if one focuses on the Early Eocene Climate Optimum (EECO) which CO₂ levels were higher than in current modern times, it appear that ECS was higher (around 4C) than the IPCC AR5 assumes (considering that we are increasing CO2 concentrations faster now that during the EECO this gives me concern rather than reassurance).

5. According to the IPCC AR5 report: "The transient climate response is likely in the range of 1.0°C to 2.5°C (high confidence) and extremely unlikely greater than 3°C"; however, the linked reference uses only observed data to indicate that TCR is 2.0 +/- 0.8C. Thus AR5 has once again erred on the side of least drama.

6. The linked reference reassesses ECS from CMIP3 &5 and find an ensemble-mean of 3.9C, and I note that CMIP3&5 likely err on the side of least drama as they ignore several important non-linear slow feedbacks that could be accelerated by global warming:

7. The linked reference could not make it more clear that paleo-evidence from inter-glacial periods indicates that ECS is meaningfully higher than 3C and that climate models are commonly under predicting the magnitude of coming climate change.

10. Sherwood et al (2014), which found that ECS cannot be less than 3C, and is likely currently in the 4.1C range. Also, everyone should remember that the effective ECS is not a constant, and models project that following a BAU pathway will result in the effective ECS increasing this century:

11. The linked reference studies numerous climate models and finds that: "… those that simulate the present-day climate best even point to a best estimate of ECS in the range of 3–4.5°C."Reto Knutti, Maria A. A. Rugenstein (2015), "Feedbacks, climate sensitivity and the limits of linear models", Philosophical Transactions of the Royal Society A, DOI: 10.1098/rsta.2015.0146

12. The linked reference indicates that the cloud feedback from tropical land is robustly positive. As AR5 did not know whether this contribution to climate sensitivity was positive or negative, this clearly indicates that AR5 errs on the side of least drama with regard to both TCR & ECS:

15. While the linked (open access) reference has many appropriate qualifying statements and disclaimers, it notes that the AR5 paleo estimates of ECS were linear approximations that change when non-linear issues are considered. In particular the find for the specific ECS, S[CO2,LI], during the Pleistocence (ie the most recent 2 million years) that: "During Pleistocene intermediate glaciated climates and interglacial periods, S[CO2,LI] is on average ~ 45 % larger than during Pleistocene full glacial conditions."

Therefore, researchers such as James Hansen who relied on paleo findings that during recent full glacial periods ECS was about 3.0C, did not know that during interglacial periods this value would be 45% larger, or 4.35C.

17. The linked open access reference identifies three constraints on low cloud formation that suggest that cloud feedback is more positive than previously thought. If verified this would mean that both TCR and ECS (and ESS) are larger than previously thought:

18. The linked article indicates that values of TCR based on observed climate change are likely underestimated:

J. M. Gregory, T. Andrews and P. Good (5 October 2015), "The inconstancy of the transient climate response parameter under increasing CO₂", Philosophical Transactions of the Royal Society A, DOI: 10.1098/rsta.2014.0417

23. The linked reference indicates that the climate responses (climate sensitivities) projected by advanced climate models generally match observations when apple to apple comparisons are made. This is a useful finding as advanced climate models generally indicate that climate sensitivity values are towards the high end of the IPCC climate sensitivity range:

24. The linked reference discusses paleodata to indicate that climate sensitivity increased from 3.3 - 5.6 (mean of 4.45k) at the beginning of the PETM up to 3.7 - 6.5 K (mean of 5.1K) near the peak of the PETM; and that if we burn only the easily accessible carbon reserves then GMST could increase by about 10C. I note these climate sensitivity values are much higher than those inherent in the CMIP5 projections:

25. The linked Reuters article notes that NASA reported that a new satellite-based method have located 39 unreported sources of anthropogenic emissions that, when accounted for, increase our previously estimated amount of sulfur dioxide by about 12 percent of all such anthropogenic emissions from 2005 to 2014. This indicates that the CMIP5 projections also underestimated the impact of this negative forcing source; which raises the prospect that climate sensitivity (ECS) is likely higher than the CMIP5 models indicate, and the linked Zhai et al (2015) reference analyses of the CMIP3&5 results conclude that the ECS is likely 3.9C +/- 0.45C:

26. The linked reference uses an information-theoretic weighting of climate models by how well they reproduce the satellite measured deseasonlized covariance of shortwave cloud reflection, indicates a most likely value of ECS of 4.0C; which indicates that AR5 errs on the side of least drama:

27. The linked article indicates that the contribution of sea-ice loss to Arctic Amplification is regulated by the PDO and that in positive PDO phases (like we are in now) there should be less Arctic Amplification. Thus the fact that we are currently experiencing high Arctic Amplification during a period of highly positive PDO values gives cause for concern that climate sensitivity may be higher than considered by AR5:

28. The linked reference uses an information-theoretic weighting of climate models by how well they reproduce the satellite measured deseasonlized covariance of shortwave cloud reflection, indicates a most likely value of ECS of 4.0C. As this satellite data is certainly biased by the recent acceleration of natural aerosol emissions associated with the increasing atmospheric CO2 concentration, the actually ECS is likely higher than 4.0C, as will become apparent if climate change reduces future plant activity. Unfortunately, the envisioned upgrades to the Paris Pact do not have any contingency for addressing such high values (4 to 4.5C) of ECS (including accelerting NET):

By how much are the CMIP5 models too optimistic because of "missing feedbacks"? Has anyone any good guesses?

I suppose we all worry about painting a picture of climate change that is so dark it becomes unbelievable to the public (Particularly if it is too pessimistic in the short term). On the other hand there is the worry about the delayers argument that climate change isn't so bad that we need to worry much about it.

The remaining carbon budget is a topics I can use in making representations to politicians, government bodies & etc. The status of the "missing feedbacks" has an important impact on this.

(EDIT: ALSR. Thanks for the homework. I was typing this at the time. It looks as if I will need time to digest it)

(EDIT2: Some students I know are organising a climate lecture in York, UK. They already have a prominent denier and are looking for a climate scientist to counter him. I suggested Kevin Anderson but I don't think he's replied yet. Any other suggestions? I'll see if I can get help with the homework!)

(EDIT2: Some students I know are organising a climate lecture in York, UK. They already have a prominent denier and are looking for a climate scientist to counter him. I suggested Kevin Anderson but I don't think he's replied yet. Any other suggestions? I'll see if I can get help with the homework!)

What is the point of debating a Gish galloper?? It is almost futile unless the climate scientist is able for a Gish gallop of his own. Countering one by one the points of a Gish gallop is a waste of time....

(EDIT2: Some students I know are organising a climate lecture in York, UK. They already have a prominent denier and are looking for a climate scientist to counter him. I suggested Kevin Anderson but I don't think he's replied yet. Any other suggestions? I'll see if I can get help with the homework!)

What is the point of debating a Gish galloper?? It is almost futile unless the climate scientist is able for a Gish gallop of his own. Countering one by one the points of a Gish gallop is a waste of time....

Basically it could become a general lecture on AGW with regular disturbances of the stupidest student. This should end up (again) by the stupidest student thinking his views are reinforced, and the listeners (hopefully) thinking this guy should be expelled. The denier will prepare with talking point memo that might have one or two hard to explain points of discussion and the scientist requiring more time than him which the inane idiot will take as break of debate rules. The rest of the memo contains shouts that interrupt explanations of inconvenient truths by the scientist thus disrupting the potential for learning for people who aren't already convinced that renewable(well ok, also nuclear, with way less highly active waste) energy is the only viable option for energy generation and transport if we as a species do not want sea levels of at least 9 meters higher and "who anyway cares what happens in 200 years, and is it 200 or 400 maybe and J.Hansen is a retired loonie."Oh, the times when talking of car and especially driver performances at the latest wc rally have taken over the discussion at the local bar that only infrequents engineers. I for one was glad to hear about the start of electric drive-train manufacturing start at the local car builder. Oh yeah. Everybody though admits you cannot get as far in a day by electric cars than by internal combustion engine and leasing a car for the summer vacation trip is beyond them. Nice.

This is starting to become a rant so I stop. Thank you for listening and remember the disadvantages of electric rail/cars and the intermittency of wind/solar.

Oh, this was the 'validation of gcms'-thread. Sorry for the last one. Validation of gcms proceeds in many steps. Firstly, you gotta get the normal ghg-effect equations so correct that you get the surface temperature to rise from the non-ghg temperature of -17,5 c (or was it -18,5°C?) to rise to the observed preindustrial temperatures. There was a lengthy explanation of further validation steps somewhere, but not on computer so not going to find and summa4rize it right away.

Please stop being so patronising. Stop the ad homs. State your case, if you have one.

A layman's view.Mr. Hunt after discovering your blog over the last few weeks I have to say your a dog for punishment. However I think we need more like you to chew up and spit out the crap of the denial industry. I love to read the past posts and the comment threads in particular. As with the ASIF the threads are always enlightening and great resources. I think I understand Mr. Williams point of view a little and think it may have more to do with predictions,(I could be way off base). Being very interested in CC for three decades or so and having most of my info coming from a list of authors to long to list it was always probably a decade old by the time it landed on the bookstore shelves. Then the IPCC reports started hitting the news in a big way at the turn of the century. Things like the Larsen B is fine for decades, gone two years later. The west Antarctic good for many decades to come and the east, millennium, both now looking unstable this century. 2c maybe this century now 4c-7c, 2c before 2050. SLR +/- 1 metre now maybe 4-5 metres. I see a lot of discussion about how they aren't really set up to do predictions. So why stick your neck out like that? I know at the regional level politicians want relevant info for planning, but if the bureaucrats at the top are dumbing down the science to render it void for that purpose it leaves the layperson thinking the science is wrong. When those of us paying attention see the next century away stuff going off every where now! I work in construction and the folks 40 to 60 years old see the changes and know something is changing for the worse. Those that look, think as I did, the models got it wrong. It's only after doing a lot of research on my own that I started to realize it was the politics that was causing the problem. I believe it to be unrealistic to think that a model that isn't robust enough to take in all the inputs,(if that's even possible), could be accurate enough for those sorts of demands. As I understand it, to have a processor big enough to run such a model, if it could even be constructed, would use most of our energy supply to run. Well we have that model now it just doesn't do print outs. We are the living print out. Point is I don't think so much that the models are wrong as incomplete. The ECS would seem to be pointing that out to our dismay. It may well be we need AI to run such a model and may even require it to build it. AI is in the foreseeable future, lets hope the ECS doesn't out run our ability to save ourselves as well as most of the flora and fauna on the planet.

You don't need AI to run any of those models. And a model is by construct incomplete. It tries to uncover the major physics and processes and it can not account for all time scales... from the chemistry of the oceans to tectonics. The more complex the model the more difficult to parse the output and make correlations that are valuable and traces back to specific physical processes. We have the real life model as you said. We have managed to only make empirical connections e.g. with El Nino we have these expected weather patterns, which some times materialize and others not.

Without the reductive nature of models we would learn nothing about the underlying physical processes.

If I am right, then nothing I/we do now makes a bit of difference. The war was lost 200 years ago.

Great, so the only reason you post here, is to vent your frustrations. That's not the intended use of the ASIF, so any more denier-mirror Dunning-Kruger BS or disrespect shown to people who engage with you and take the time to refer you to stuff (the 'herd' of persecutors), and I'm putting you under moderation.

Your actions and what you say don't match. A true doomer wouldn't be wasting time on some obscure forum. He'd be listening to Bach and reading Tolstoy. Go punch a bag or something.

Perhaps this thread should be renamed: "If Decision Makers Don't Care to Take Effective Action, Why Should Scientists Work to Refine Their Imperfect GCM Models?"

To bear witness. To leave a record.

As Neven pointed out, the ASIF is doing a good job of documenting the decline of the Arctic Sea Ice for the good of posterity.

Yes, and the need has never been greater with the prospect of climate science being cut off at the knees in the USA. But I am veering in the direction of policy, actions, solutions and can feel a moderator hovering over the delete button. So je suis fini.

Logged

"Para a Causa do Povo a Luta Continua!""And that's all I'm going to say about that". Forrest Gump"Damn, I wanted to see what happened next" (Epitaph)

While the entire video is worth watching I provide the first attached image/screen shot showing DeConto & Pollard's (2016 EGU) projections of Antarctic contributions to changes in global mean sea level, GMSL, by the 2C (blue line), 2.7C (green line) and 3.6C (red line) forcing scenarios. I believe that DeConto & Pollard's 2C scenario is not achievable in the real world, and that by 2100 the 2.7C and the 3.6C forcing scenario produce essentially the same amount of increase in GMSL. Taken together with the more "Realistic" MIT analysis the DeConto & Pollard (2016 EGU) findings indicate it likely that the WAIS collapse will begin about 2050 following the current Paris Pact pledges (and also ignoring the increase in carbon emissions associated with increasing agricultural growth).

Also I note that the indicated DeConto & Pollard (2016 EGU) findings do not include Hansen et al (2016)'s ice-climate feedback and thus errs on the side of least drama (see the last two images).

Maybe instead of measuring increases in GMSTA, we should be focused on monitoring biodiversity loss, as without sufficient biodiversity mankind's future is in doubt.

The linked article is entitled: “Ecological recession”: Researchers say biodiversity loss has hit critical threshold across the globe". The article references both Newbold et. al. 2016 and Steffen et. al. (2015); both of which indicate that we are already exceeding some planetary boundaries, and will soon exceed others.

Extract: "An international team of researchers has concluded that biodiversity loss has become so severe and widespread that it could affect Earth’s ability to sustain human life.…- The researchers examined 2.38 million records of 39,123 terrestrial species collected at 18,659 sites around the world to model the impacts on biodiversity of land use and other pressures from human activities that cause habitat loss.

- They then estimated down to about the one-square-kilometer level the extent to which those pressures have caused changes in local biodiversity, as well as the spatial patterns of those changes.

- They found that, across nearly 60 percent of Earth’s land surface, biodiversity has declined beyond “safe” levels as defined by the planetary boundaries concept, which seeks to quantify the environmental limits within which human society can be considered sustainable.

AbstractLand use and related pressures have reduced local terrestrial biodiversity, but it is unclear how the magnitude of change relates to the recently proposed planetary boundary (“safe limit”). We estimate that land use and related pressures have already reduced local biodiversity intactness—the average proportion of natural biodiversity remaining in local ecosystems—beyond its recently proposed planetary boundary across 58.1% of the world’s land surface, where 71.4% of the human population live. Biodiversity intactness within most biomes (especially grassland biomes), most biodiversity hotspots, and even some wilderness areas is inferred to be beyond the boundary. Such widespread transgression of safe limits suggests that biodiversity loss, if unchecked, will undermine efforts toward long-term sustainable development.

Perhaps this thread should be renamed: "If Decision Makers Don't Care to Take Effective Action, Why Should Scientists Work to Refine Their Imperfect GCM Models?"

To bear witness. To leave a record.

As Neven pointed out, the ASIF is doing a good job of documenting the decline of the Arctic Sea Ice for the good of posterity.

Yes, and the need has never been greater with the prospect of climate science being cut off at the knees in the USA. But I am veering in the direction of policy, actions, solutions and can feel a moderator hovering over the delete button. So je suis fini.

At least we will be able to tell future generations that we were fully aware of what was happening as we carefully documented the slide down to the collapse.

Obviously Jim's position is rather doctrinaire on this topic. I don't know that much about GCMs but I tend to agree with him that at the end of the day, their utility in helping to understand the climate crisis, and respond to it, will be very limited. For example, and yes I understand that the time scales are wrong, but the very warm non el nino driven global temps of the past two months are surprising, alarming and suggest that our overall understanding of the climate system is dangerously limited.

AbstractPhase 5 of the Coupled Model Intercomparison Project (CMIP5) climate models’ projections of the 2014–2100 Arctic warming under radiative forcing from representative concentration pathway 4.5 (RCP4.5) vary from 0.9° to 6.7°C. Climate models with or without a full indirect aerosol effect are both equally successful in reproducing the observed (1900–2014) Arctic warming and its trends. However, the 2014–2100 Arctic warming and the warming trends projected by models that include a full indirect aerosol effect (denoted here as AA models) are significantly higher (mean projected Arctic warming is about 1.5°C higher) than those projected by models without a full indirect aerosol effect (denoted here as NAA models). The suggestion is that, within models including full indirect aerosol effects, those projecting stronger future changes are not necessarily distinguishable historically because any stronger past warming may have been partially offset by stronger historical aerosol cooling. The CMIP5 models that include a full indirect aerosol effect follow an inverse radiative forcing to equilibrium climate sensitivity relationship, while models without it do not.

Obviously Jim's position is rather doctrinaire on this topic. I don't know that much about GCMs but I tend to agree with him that at the end of the day, their utility in helping to understand the climate crisis, and respond to it, will be very limited. For example, and yes I understand that the time scales are wrong, but the very warm non el nino driven global temps of the past two months are surprising, alarming and suggest that our overall understanding of the climate system is dangerously limited.

I find almost all of the cartoon images that I post using GOOGLE, & thus I do not know the original source. Therefore, if you want to retro search for the origins of the images you can use one of the following tools:

On April 22nd The March for Science will endeavor to teach the Trump Administration the errors of its thinking.

ASLR, not sure why you append this article to my post. Orrin Pilkey, the author of the book is "Professor Emeritus of Earth and Ocean Sciences, Nicholas School of the Environment, at Duke University, and Founder and Director Emeritus of the Program for the Study of Developed Shorelines (PSDS) which is currently based at Western Carolina University."

I certainly did not intend my post to be anti-science! I'm a PhD ecologist and will be at the march. But that does not mean that numerical modeling has an outstanding record of success. There is a lot more to science than just modeling and I'm not sure why you are conflating the two as somehow inseparable. Here is some more content from his Wikipedia page:

Pilkey began his career with the study of abyssal plains on the deep sea floor. As a result of the destruction of his parents' house in Waveland, Mississippi in Hurricane Camille (1969), he switched to the study of coasts. Pilkey's research centers on both basic and applied coastal geology, focusing primarily on barrier island coasts and the effects of shoreline stabilization and development, and sea-level rise. The PSDS has analyzed the numerical models used by coastal geologists and engineers to predict the movement of beach sand, especially in beach replenishment. In general, Pilkey argues that mathematical models cannot be used to accurately predict the behavior of beaches, although they can be useful if directional or orders-of-magnitude answers are sought. In the book, Useless Arithmetic, written with his daughter, Linda Pilkey-Jarvis, they argue that the outcome of natural processes in general cannot be accurately predicted by mathematical models.[1]

ASLR, not sure why you append this article to my post. Orrin Pilkey, the author of the book is "Professor Emeritus of Earth and Ocean Sciences, Nicholas School of the Environment, at Duke University, and Founder and Director Emeritus of the Program for the Study of Developed Shorelines (PSDS) which is currently based at Western Carolina University."

I certainly did not intend my post to be anti-science! I'm a PhD ecologist and will be at the march. But that does not mean that numerical modeling has an outstanding record of success. There is a lot more to science than just modeling and I'm not sure why you are conflating the two as somehow inseparable. Here is some more content from his Wikipedia page:

Pilkey began his career with the study of abyssal plains on the deep sea floor. As a result of the destruction of his parents' house in Waveland, Mississippi in Hurricane Camille (1969), he switched to the study of coasts. Pilkey's research centers on both basic and applied coastal geology, focusing primarily on barrier island coasts and the effects of shoreline stabilization and development, and sea-level rise. The PSDS has analyzed the numerical models used by coastal geologists and engineers to predict the movement of beach sand, especially in beach replenishment. In general, Pilkey argues that mathematical models cannot be used to accurately predict the behavior of beaches, although they can be useful if directional or orders-of-magnitude answers are sought. In the book, Useless Arithmetic, written with his daughter, Linda Pilkey-Jarvis, they argue that the outcome of natural processes in general cannot be accurately predicted by mathematical models.[1][/quote]

dnem,

I apologize for any confusion that my post may have contributed to (I believe I posted too quickly); as indeed Orrin Pilkey does fight against anti-science efforts.

Here is a link to an article co-authored by Orrin Pilkey were he fights against anti-science efforts in North Carolina:

However, I do believe that this illustrates how complicated the challenge is of trying to motivate decision makers to follow the Precautionary Principle when denialist can just say that the model in question gives projections that are not sufficiently accurate, so they must use their own personal judgment to cancel funding to support such climate research as the current administration is doing.

Logged

“It is not the strongest or the most intelligent who will survive but those who can best manage change.” ― Leon C. Megginson

There is a very big propagation error in the models' forecasts, as evaluated in this paper regarding the forecasting accuracy of GCM models: Propagation of Error and the Reliability of Global Air Temperature Projections

From the abstract: "Propagation of LWCF /long-wave cloud forcing/ thermal energy flux error through the historically relevant 1988 projections of GISS Model II scenarios A, B, and C, the IPCC SRES scenarios CCC, B1, A1B, and A2, and the RCP scenarios of the 2013 IPCC Fifth Assessment Report, uncovers a ±15 C uncertainty in air temperature at the end of a centennial-scale projection. Analogously large but previously unrecognized uncertainties must therefore exist in all the past and present air temperature projections and hindcasts of even advanced climate models."

"CMIP5 error in LWCF implies that the magnitude of the thermal energy flux within the atmosphere is simulated incorrectly. This climate model error represents a range of atmospheric energy flux uncertainty within which smaller energetic effects cannot be resolved within any CMIP5 simulation. ... the source of calibration error is inherent within the physical theory deployed by CMIP GCMs. This means that the error in LWCF arises in the GCM and enters into every step of a simulation. Each step includes a fresh simulation of cloud cover; and each fresh simulation will include a LWCF thermal flux error. An inherently incorrect theory puts its intrinsic error into every simulation step. "

From the conclusions: "LWCF calibration error is ±114 × larger than the annual average increase in GHG forcing. This fact alone makes any possible global effect of anthropogenic CO2 emissions invisible to present climate models. At the current level of theory an AGW signal, if any, will never emerge from climate noise no matter how long the observational record because the uncertainty width will necessarily increase much faster than any projected trend in air temperature. Any impact from GHGs will always be lost within the uncertainty interval. Even advanced climate models exhibit poor energy resolution and very large projection uncertainties."

Conclusion from reading this paper seems to be that it would be better to refrain from making any forecasts with the GCM models examined, as they have no predictive value.

Response: No and no. Frank confuses the error in an absolute value with the error in a trend. It is equivalent to assuming that if a clock is off by about a minute today, that tomorrow it will be off by two minutes, and in a year off by 365 minutes. In reality, the errors over a long time are completely unconnected with the offset today. – gavin

KiwiG,the error handling of GCM models used for forecasting is actually a highly debatable issue. You give a quote by Gavin Schmidt who compares climate models with a clock. Beforehand, we don't know why the clock is lagging one minute. Yes, it can be a stochastic error, but it can also be a systematic error.A clock that lags with 1 minute per day will indeed lag by 365 minutes after a year, that's the lower error bound. In retrospect, this clock demonstrates a systemic error, not a stochastic error. But beforehand we can't know what kind of error the clock has inside its mechanism.The quote from GS is not really that clarifying.

Climate models do have severe problems handling the most potent GHG of them all: water vapor/clouds. Water vapor plays a key role in the global climate system 1) it is the most abundant and the most radiatively important greenhouse gas, 2) can transport large amounts of latent heat and thus strongly influences the dynamics of the atmosphere3) is an important link connecting the various components of the hydrological cycle.

What Frank's paper says, is essentially that the forecasting abilities of GCMs are indistinguishable from linear extrapolation of GHG forcing with accumulating uncertainty. Having worked for many years with stochastic models in economics/finance, and knowing that climate is a highly stochastic chaos system where the main GHG is extremely poorly modelled, I don't expect any other conclusion than what P.Frank comes up with. Of course uncertainty will be accumulating over forecast time.I agree that some details in the paper are debatable, but there is nothing strange in his findings, nor does there seem to be fundamental errors in his approach.You say it's "garbage", I say it's healthy criticism of models built on dubious modelling and assumptions regarding the most important GHG.

Weather is unforecastable, hurricanes are unforecastable. Climate is forecastable as long as it develops more or less linearly, which is what it has been doing for the latest decades. That's what Frank demonstrates. Which should be a wake up call for anyone believing in GCM models such as the IPCC crowd.

What if feedback mechanisms kick in, and climate starts to behave as stochastically as weather?!? GCM models aren't programmed for that AFAIK, they, and even IPCC, disregards feedback loops etc.

I deeply distrust any kind of models built on crappy inputs. 'GCM models don't even have the data for the strongest GHG (water vapor/clouds) as they operate on larger grids than clouds. And even if they got the data, computing capacity isn't big enough. And even if they got the data AND the computing capacity, they still lack a general theory on water vapor on various latitudes and altitudes. We are very very far from having anything reliable in the field of GCM modelling.

Still, Frank's paper is mostly 'garbage' on technical grounds, as thoroughly demonstrated in this link:

That's overstated. We now have very useful and reliable weather and hurricane forecasts. They are not perfect, but they are certainly useful and the days of communities being hit unawares by hurricanes are thankfully decades in the past.

Weather is unforecastable, hurricanes are unforecastable. Climate is forecastable as long as it develops more or less linearly, which is what it has been doing for the latest decades. That's what Frank demonstrates. Which should be a wake up call for anyone believing in GCM models such as the IPCC crowd.

Weather is not climate.The models are not perfect but they are useful.To perturb climate you need a forcing. Volcanoes do not operate linearly but GSM can still project their effects on climate accurately . We have know from modeling that increasing CO2 will result in the earths surface Warming for over a hundred years. The IPCC is not an isolated group its reports are distilled from the work of tens of thousands of scientists. All work publish in the fields it covers is considered. Even gibbering nonsense like Pats will be examined in the process. Write off the IPCC like you just did is loony tune science denial .

The attached graph compares observations of global temperature with CMIP5 simulations assessed by the IPCC 5th Assessment Report. The figure is an updated version of Figure 11.25a from IPCC AR5 which was originally produced in mid-2013.

The graph shows the raw ‘spaghetti’ projections of the 90 or so models used, with different observational datasets in black and the different emission scenarios (RCPs) shown in colours.

Observations are on the lower side of the projections. Could there be something wrong with how the models handle forcings? Yes, there could.